This application relates to antiviral tissue paper comprising pyrrolidone carboxylic acid. When added to tissue paper pyrrolidone carboxylic acid has the ability to kill certain strains of viruses which come into contact with the tissue. In addition to its antiviral efficacy, pyrrolidone carboxylic acid is mild to the skin thus mitigating the potential for skin irritation. This application further relates to antiviral lotions comprising pyrrolidone carboxylic acid. A process for making the antiviral tissue paper of this invention is also disclosed.
Whether it be a household, workplace, educational facility or any other location where people tend to gather, preventing the spread of germs is a difficult but yet desirable task. For instance, it is well documented that many hours of productive work are lost due to individuals becoming infected with the common cold or influenza virus.
When one suffers from the common cold or influenza virus, one""s mucus is the source of a very high concentration of viruses. After the mucus is aerosolized by a sneeze, cough, or other environmental surfaces, the virus within the mucus has the potential to infect other individuals coming into contact with it. Likewise, mucus deposited into a facial tissue also has the potential to infect others if they come in contact with the contaminated tissue. Transfer of this mucus on the tissue to another individual will likely be through accidental or unintentional contact.
As an example of a possible transfer scenario, consider a cold sufferer who accidentally leaves a mucus infected facial tissue on a hard surface of some type. This hard surface might be a kitchen countertop, a bathroom vanity surface, an office desk or some other piece of furniture. Another family member or colleague may accidentally come into contact with the infected mucus after picking up the tissue to throw it away or by contacting the contaminated countertop area. After coming into such contact with the mucus on the tissue, it is very possible for that individual to become infected with the viral condition (i.e., common cold, influenza) especially if the infected mucus comes into contact with that individual""s mucosal membranes.
Another transmission scenario is through the disposal of the facial tissues contaminated with the virus containing mucus. After a household waste basket becomes filled with trash containing a high concentration of infected tissues, it obviously needs to be disposed of in some manner. During this transfer of the household trash into another larger disposal unit, the individual transferring the trash may come into contact with the contaminated tissue. Once again, this individual is at a higher risk for contracting the virus. Many other potential modes of virus transmission are possible after the facial tissue has become infected with the mucus.
Furthermore, virus transmission is not the only concern when one has a cold. As is well known, cold and influenza sufferers typically have sore and irritated skin regions associated with the nose and lips. The irritation, inflammation and redness around the nose and lips can have several causes. A prime one is, of course, the sheer necessity of frequently blowing one""s nose into he tissue, and wiping the resultant nasal discharge from the nose and surrounding area.
The degree of irritation and inflammation caused by such blowing and wiping is directly proportional to: (1) the surface roughness of the tissue used; (2) the number of times the nose and its surrounding areas are in contact with the tissue; and (3) the irritation potential of any additives applied to the tissue paper. It is thus imperative to use antiviral compositions that are as mild as possible.
U.S. Pat. No. 4,738,847 issued to Rothe et al. on Apr. 19, 1988 purports to teach a three ply cellulosic tissue wherein a virucidal composition is substantially confined to the center ply. The virucidal composition is composed of citric acid and/or malic acid. A surfactant, sodium lauryl sulfate, may also be included.
U.S. Pat. No. 4,828,912 issued to Hossain et al. on May 9, 1989 purports to teach a virucidal composition applied to a tissue. The virucidal composition may include citric, malic, succinic, and/or benzoic acid. A surfactant may also be included.
Both of these suffer from the same drawback. The virucidal compositions are not mild to the skin.
The antiviral agent(s) of the present invention is effective at killing certain strains of viruses such as influenza virus and rhinovirus. Furthermore, it is very mild to the skin. Additionally, it provides a unique residual effect where upon transfer from the tissue to the user, the antiviral agent can potentially protect those skin regions which come in contact with the viral infections. Furthermore, because the antiviral agent tends to be mild, the potential for skin irritation and stinging in these areas is greatly reduced. As the potential for skin irritation and stinging is reduced, the antiviral agent may be placed on the outer plies of the tissue product whereby it can easily be transferred directly to the skin. Yet further, this allows for more immediate contact of the antiviral agent with the mucosal discharge. Hence, the antiviral agent does not have to be confined to the inner plies of the tissue.
Yet further, the antiviral agent of the present invention tends to promote retention of the skin""s natural moisture. With regard to retention of the skin""s natural moisture there is much described in cosmetics literature that directly correlates skin health with moisture content of the stratum corneum (I. H. Blank, J. Invest. Dermatol., 18, 433 (1952); L. F. Gaul et al., J. Invest. Dermatol., 19, 9 (1952); O. K. Jacobi, J. Soc. Cosmet. Chem., 18, 149 (1967)).
The factors controlling skin moisture content comprise water soluble materials called Natural Moisturizing Factors (hereinafter referred to as xe2x80x9cNMFxe2x80x9d) (O. K. Jacobi, J. Soc. Cosmet. Chem., 18, 149 (1967)); H. W. Spier et al., Hautarzt, 7, 2 (1956)); and lipids of the skin surface.
As the name denotes, NMF is found naturally in human skin primarily in the stratum corneum. The composition of NMF as documented by Spier et al. (Hautarzt, 7, 2, 1956), is a variety of free amino acids; lactates; urea; pyrrolidone carboxylic acid and the corresponding salts; and other organic derivatives and mineral salts.
Effects of the NMF constituents have been studied extensively for skin moisturization transepidermal water loss; and skin elasticity (Reiger, M., J. Soc. Cosmetic Chem., 35, 253 (1974)).
Although the mode of action has not been entirely elucidated, Laden et al. (J. Soc. Cosmetic Chem., 18, 351, (1967)) has determined that pyrrolidone carboxylic acid and its corresponding sodium salt are important components for skin moisturization and improving skin suppleness (Laden et al., J. Soc. Cosmetic Chem., 21, 417 (1970)).
This has been further supported by Clar et al. (International Journal of Cosmetic Science, 3, 101, (1981)) and Middleton et al. (J. Soc. Cosmetic Chem., 29, 201, (1978)) where creams and lotions containing pyrrolidone carboxylic acid and sodium pyrrolidone carboxylate are reported to improve skin hydration and reduce dry flaky skin. Other components in NMF such as lactate also improve water retention of the epidermis to a lesser extent than pyrrolidone carboxylic acid.
Hence, the present invention provides a surprising combination of unique properties including immediate and residual antiviral efficacy, mildness, and the potential to assist with the retention of the skin""s natural moisture.
The benefits of utilizing the tissue product of the present invention include a tissue product that is effective at preventing the spread of certain cold and flu viruses while being comfortable to use and potentially providing additional skin benefits to the user.
The present invention relates to antiviral tissues that are mild to the skin. The antiviral tissue product comprises one or more fibrous ply(ies) and an antiviral composition. The antiviral composition comprises pyrrolidone carboxylic acid. The pyrrolidone carboxylic acid may comprise from about 0.05% to 50% by weight of the antiviral tissue product. The antiviral composition may further comprise a metal salt. It may also include a surfactant. An optional organic acid may also be added. The antiviral tissue product may also contain a wet strength resin.
The antiviral tissue product may also include a lotion. The lotion may comprise polysiloxane. The lotion may also include an antiviral composition such as pyrrolidone carboxylic acid, citric acid, malic acid, lactic acid, glutaric acid, succinic acid, or mixtures thereof.
The antiviral tissue may optionally include a moisture barrier. The moisture barrier may include an antiviral composition.
The antiviral tissue product may have an xe2x80x9cEasiness to Loosen in Waterxe2x80x9d test value of greater than about 100 seconds.
The present invention also relates to a process for making an antiviral tissue product.